In 3GPP (3rd Generation Partnership Project), standardization of the third generation (3G) UTRA (Universal Terrestrial Radio Access) as the cellular mobile communication system is underway, and its services are launched in sequence (e.g., non-patent literature 1). Standard formulation of the evolution of third generation radio access, EUTRA (Evolved Universal Terrestrial Radio Access) is also in progress (e.g., non-patent literature 1). Furthermore, IMT-Advanced is under consideration as the fourth generation (4G) radio access.
IMT-Advanced assumes realization of 100 Mbps for high speed movement and even 1 Gbps for high speed movement, with its available frequency band determined in WRC07 (World Radio Conference 07) held by ITU-R (International Telecommunication Union Radio communications Sector) in the autumn of 2007. Standard formulation works subsequently became active through 2008 to 2009, and its services are expected to be launched in 2010 or later.
ITU-R has determined, as new frequency band for the 3G and 4G mobile communication system (IMT: International Mobile Telecommunication) to be used globally, a 200 MHz width of 3.4 to 3.6 GHz, a 100 MHz width of 2.3 to 2.4 GHz, a 108 MHz width of 698 to 806 MHz, and a 20 MHz width of 450 to 470 MHz, specifically. Each country will allocate actual frequencies for IMT from the above, according to circumstances in its own country. In the future, each country will deploy IMT-Advanced services utilizing IMT-2000 Plan Band assigned to 3G and IMT Band newly assigned to 3G and 4G. However, considering provision of IMT-Advanced services from plural carriers to a single area, it is difficult for a single carrier to secure a continuous 100 MHz band for IMT-Advanced. Additionally, although it is easy to secure a wide band in a high-frequency band (e.g., 3 GHz or higher), there is difficulty in securing a wide continuous cell cover area and supporting high speed movement because of significant radio propagation attenuation in wide band/high frequencies.
Furthermore, existing carriers providing second generation (2G) and third generation (3G) mobile communication services may consider that it is desirable to provide IMT-Advanced services based on existing base station locations, and therefore they may have a negative attitude toward introducing new technology with regard to base station placement or new facility addition such as a repeater station, a relay station, or DWCS (Distributed Wireless Communication Systems).
Before considering INRI (IMT-Advanced New Radio Interface(s)), it is necessary to deliberate the method, system configuration, or radio channel configuration for frequency bands, taking into account the IMT Band for which securing a 100 MHz band is difficult.
There have been proposed, as conventional technologies, a method which supports non-symmetric amounts of communication by switching between a plurality of wireless multiple-access methods in a plurality of frequency bands to effectively utilize frequencies (e.g., patent literature 1), a method which detects reserved capacity of FDD (Frequency Division Duplex) and assigns it to a TDD (Time Division Duplex) mobile station facility (e.g., patent literature 2), or a method which configures a system using a plurality of frequency bands to increase the downlink data transmission speed (e.g., patent literature 3).
Particularly, as the method which configures a system using a plurality of frequency bands to increase the downlink data transmission speed (e.g., patent literature 3), for a mobile communication system including a main frequency band having a single frequency bandwidth BW1 and a sub-frequency band having a plurality of frequency bandwidths BW2 and BW3, a method is proposed, which performs, as shown in FIG. 13, communication via one frequency bandwidth (e.g., BW2: Band Width 2) of the sub-frequency band in addition to the main frequency band, according to the inherent ability of the mobile station apparatus, i.e., category of the mobile station apparatus (UE categories), and it is proposed that at least one frequency bandwidth (e.g., BW3) in the sub-frequency band supports the downlink only.
(A) Explanation of a Cell Common Channel and a Cell Dedicated Channel
Downlink radio channels include radio common channels required to cover the entire cell area and assure a predetermined reception quality in a mobile station apparatus at the cell edge. These radio common channels, which employ, for example, a low-rate modulation system such as BPSK: Binary Phase Shift Keying or QPSK: Quadrature Phase Shift Keying, an encoding system with high redundancy, and radio transmission system that is highly-resistant to interference such as iterative transmission along the time/frequency axis, or a spread spectrum system with a high spreading factor, assure predetermined reception quality down to the cell edge. Generally, because the radio resource to be used by each radio channel is limited, the radio common channel has a low data transmission speed in order to assure a predetermined reception quality.
As common transmission data in a mobile communication system, control data of a mobile communication system, such as identical synchronization data, broadcast data or common control data, i.e., a radio common control channel, and broadcast data for providing services to a plurality of mobile station apparatuses (e.g., MBMS data described below), i.e., a radio common traffic channel, are transmitted to a plurality of mobile station apparatuses, for example. Here, a radio common control channel and a radio common traffic channel required to cover the entire cell area and assure a predetermined reception quality down to a mobile station apparatus at the cell edge are respectively referred to as DCCCCH (Downlink Cell Common Control Channel) and DCCTCH (Downlink Cell Common Traffic Channel).
Downlink radio channels, on the other hand, include radio dedicated channels required to assure a predetermined reception quality down to a mobile station apparatus moving within a cell area without having to cover the entire cell area. These radio dedicated channels set the modulation system according to the distance between the mobile station apparatus and the base station apparatus, radio propagation loss, variation of radio propagation signal power, or the like. If, for example, a radio propagation loss between the mobile station apparatus and the base station apparatus is large, a low-rate modulation system, such as BPSK or QPSK, an encoding system with high redundancy, and a radio transmission system that is highly-resistant to interference such as iterative transmission along the time/frequency axis, a spread spectrum system with a high spreading factor, or high transmission power are used, whereas a high-rate modulation system such as 16 QAM (16 Quadrature Amplitude Modulation) or 64 QAM, an encoding system with low redundancy, and wireless transmission methods having a high data transmission speed with a low transmission power such as no iterative transmission along the time/frequency axis, a spread spectrum system with a low spreading factor, and low transmission power are used if radio propagation loss between the mobile station apparatus and the base station apparatus is small, which assures a required reception quality of the mobile station apparatus.
As individual transmission data in a mobile communication system, there are, for example, user data to individual mobile station apparatuses, i.e., a radio dedicated traffic channel, and radio resource allocation information data of user data and user data demodulation information data such as degree of modulation/encoding system, i.e., a radio dedicated control channel. Here, a radio dedicated channel and a radio dedicated traffic channel required to assure a predetermined reception quality down to a mobile station apparatus moving within a cell area without having to cover the entire cell area, are respectively referred to as DCDCCH (Downlink Cell Dedicated Control Channel) and DCDTCH (Downlink Cell Dedicated Traffic Channel).
(B) Explanation of Downlink Radio Frame Configuration of EUTRA (Non-Patent Literature 2)
EUTRA technology specification document of 3GPP describes a downlink radio access technology of EUTRA. FIG. 6 illustrates a radio frame configuration of the downlink of EUTRA. With regard to assignment of downlink radio channels, a method is employed which multiplexes time and frequencies with TDM (Time Division Multiplexing), FDM (Frequency Division Multiplexing), or a combination of TDM and FDM, using resources of the frequency axis (in units of subcarrier) and the time axis (in units of OFDM symbol) of OFDM (Orthogonal Frequency Division Multiplexing) signals, as shown in FIG. 6. The downlink radio frame is composed of a frequency bandwidth Bch which is a collection of a plurality of subcarriers along the frequency axis direction and a plurality of two-dimensional PRBs (Physical Resource Block) by the SF (Sub-frame) of the time axis. For example, on the frequency axis, the entire downlink spectrum (system frequency bandwidth BW specific to the base station) is set to 20 MHz, the frequency bandwidth Bch of PRB is set to 180 kHz, the subframe SF is set to 0.5 ms, the subcarrier frequency bandwidth Bsc is set to 15 kHz, and a single radio frame is set to 10 ms. Twelve subcarriers and one subframe compose a radio physical resource block PRB. Ts denotes the OFDM symbol length. Additionally, a known RS (Reference Signal) or a PS (Pilot Signal) is inserted in the radio frame for data demodulation and measurement of downlink radio channel condition.
(C) Explanation of Radio Channel Configuration in EUTRA (Non-Patent Literature 3)
EUTRA technology specification document of 3GPP describes a radio channel configuration of EUTRA. As shown in FIG. 9, the uplink uses the natural frequency bandwidth BW of the base station apparatus and the following radio physical channels are mapped. PRACH (Physical Random Access Channel) transmits RACH (Random Access Channel) of the transport channels with a random access preamble. RACH is used at the time of initial access, handover, or when uplink or downlink communication data is generated. RACHs can be classified into the collision type in which RACHs from respective mobile station apparatuses collide on the radio resource and the non-collision type in which RACHs from respective mobile station apparatuses can be separated on the radio resource.
PUCCH (Physical Uplink Control Channel) transmits control information from the mobile station apparatus. With PUCCH, the mobile station apparatus is used, according to the downlink reception conditions, for HARQ (Hybrid Automatic Repeat Request), an affirmative response ACK (Acknowledgement) or a negative response NAK (Negative Acknowledgement), transmission of information bits, transmission of SR (Scheduling Request) information bits requesting allocation of uplink radio resource to the base station apparatus, transmission of information bits of downlink CQI (Channel Quality Indicator) estimated by the mobile station apparatus, transmission of the number of data streams NLR (Number of Layers Rank, which depends on the number of transmission antennas) and transmission PCI (Pre-coding Codebook Index) information bits of a base station apparatus selected according to the reception conditions of the mobile station apparatus, or transmission of control information bits such as the result of measurement of the mobile station apparatus. PUSCH (Physical Uplink Shared Channel) transmits UL-SCH (Uplink Shared Channel) of the transport channel.
CCCH (Common Control Channel), DCCH (Dedicated Control Channel), and DTCH (Dedicated Traffic Channel) of logical channels are included. CCCH, which transmits control signals between a plurality of mobile station apparatuses and a mobile communication network, is used in a state other than the RRC_CONNECTED Mode. DCCH, which transmits control signals between individual mobile station apparatuses and the mobile communication network, is used in the state of the RRC_CONNECTED Mode. DTCH, which is a one-to-one channel between the mobile communication network and the individual mobile station apparatuses, is used for transmitting uplink user data. Additionally, a part of the control information bits can be transmitted using a part of the radio resource of PUCCH, instead of PUCCH.
The downlink uses the natural frequency bandwidth BW of the base station apparatus. As shown in FIGS. 6 and 9, the radio physical channel described below is mapped. SCH (Synchronization Channel) is inserted in the downlink radio frame. SCH is used for initial synchronization of OFDM reception signals, cell selection, and cell search for reselection or cell handover during communication, for example. SCH includes carrier frequency offset synchronization, OFDM symbol timing synchronization, radio frame timing synchronization, related information of specific CPID (Cell Physical Identification), related information of the cell physical configuration, or the like. SCH is composed of two subchannels, a P-SCH (Primary SCH) and an S-SCH (Secondary SCH). The P-SCH and the S-SCH are downlink cell common control channels DCCCCH.
PBCH (Physical Broadcast Channel) transmits broadcast information such as system information or cell information. PBCH is a downlink cell common control channel DCCCCH. PDSCH (Physical Downlink Shared Channel) transmits DL-SCH (Downlink Shared Channel) of the transport channel and PCH (Paging Channel). DL-SCH includes BCCH (Broadcast Control Channel) of the logical channel, CCCH (Common Control Channel), DCCH (Dedicated Control Channel), DTCH (Dedicated Traffic Channel), MCCH (Multicast Control Channel), and MTCH (MBMS Traffic Channel) of MBMS (Multimedia Broadcast Multicast Service).
The paging channel PCH includes PCCH (Paging Control Channel) of the logical channel. As transmission methods of MBMS, there are a method in which only one base station performs transmission and a method in which a plurality of base stations synchronizing with time and frequency perform transmission simultaneously. The former is referred to as SCPTM (Single-Cell Point-to-Multipoint) and the latter is referred to as MBSFN (Multimedia Broadcast multicast service Single Frequency Network). As for MBMS transmission signals of a MBSFN cell that provides MBSFN service, identical MBMS signals are simultaneously transmitted by a plurality of base station apparatuses so that MBMS reception signals of a plurality of MBSFN cells can be synthesized for the mobile station apparatus. MCCH and MTCH are downlink cell common traffic channels DCCTCH for the case of an MBSFN cell. BCCH, CCCH and PCCH are downlink cell common control channels DCCCCH. DTCH is a downlink cell dedicated traffic channel DCDTCH. DCCH is a downlink cell dedicated control channel DCDCCH.
PDCCH (Physical Downlink Control Channel) transmits radio resource allocation information bits of DL-SCH and PCH of the transport channel included in PDSCH, information bits of HARQ associated with DL-SCH, and Uplink scheduling grant signaling. PDCCH is a downlink cell dedicated control channel DCDCCH.
PHICH (Physical Hybrid ARQ Indicator Channel) transmits Hybrid ARQ ACK/NAKs information bits corresponding to uplink PUSCH. PHICH is a downlink cell dedicated control channel DCDCCH. PCFICH (Physical Control Format Indicator Channel) transmits information bits of the number of OFDM symbols to be used by the physical downlink control channel PDCCH. PCFICH is a downlink cell common control channel DCCCCH.
PMCH (Physical Multicast Channel) transmits a multicast transport channel (MCH: Multicast Channel). Similarly to DL-SCH, to MCH there can be assigned MCCH and MTCH, which are used for MBMS.
Although there are descriptions of the above-mentioned MBSFN and SCPTM with regard to MCCH and MTCH, as shown in FIG. 9, here we temporarily define MCCH and MTCH as a downlink cell common traffic channel DCCTCH in case of MBSFN cell and define them as a downlink cell dedicated traffic channel DCDTCH in case of SCPTM, because their specification is under consideration. Hereinafter, the specification will be adhered to.    Patent Literature 1: Japanese Patent No. 3802372    Patent Literature 2: Translated Japanese Publication of Patent Application No. 2002-521988    Patent Literature 3: Translated Japanese Publication of Patent Application No. 2007-505583    Non-patent Literature 1: 3GPP TS 25.211,V7.0.0 (2006-03), Physical channels and mapping of transport channels onto physical channels.    http://www.3gpp.org/ftp/Specs/html-info/25-series.htm    Non-patent Literature 2: 3GPP TS 36.211,V8.1.0 (2007-12), Physical Channels and Modulation.    http://www.3gpp.org/ftp/Specs/html-info/36211.htm    Non-patent Literature 3: 3GPP TS 36.300,V8.3.0 (2007-12), Overall description;Stage2.    http://www.3gpp.org/ftp/Specs/html-info/36300.htm